The present disclosure relates generally to pressure regulation systems, and more particularly to thermally responsive pressure valves used in anti-icing systems for aircraft.
Operation of aircraft engines in adverse weather conditions or at high altitudes can sometimes lead to ice forming on the exposed surfaces of the engine nacelle inlet. The build-up of ice on a nacelle surrounding the engine limits the quantity of air being fed to the engine. This reduction in inlet airflow can result in a reduction of power output, efficiency and/or cooling capacity of the engine. Engine inlet anti-icing systems commonly employ a thermal source, such as hot air bled from the engine core, which is applied to the nacelle inlet to prevent ice build-up on the external surfaces thereof.
Another concern with aircraft engines is the useful life of the aircraft engine and components. The build-up of ice near the inlet of the engine may lead to large pieces of ice breaking loose from the inlet and flowing into the gas turbine engine. Ice flowing into and through the engine may damage components within the engine, such as the blades, and components attached to the nacelle, such as inlet acoustic panels. The damaged components may then require repair or replacement.
Current anti-icing systems include valves that do not compensate for increases in bleed air temperature with increasing bleed pressure and as a result, delivered heat flux which is a function of flow times bleed air temperature can result in damage to the nacelle.